Regioselective reduction of fused pyrrolocarbazole-5,7-diones

摘要

The present invention relates to a method for regioselectively reducing the maleimide compounds of formula (I). The invention also relates to C 7 hydroxy lactam regioisomers of formula (II) obtainable by this method and their use for the preparation of lactams of formula (Ill) which are particularly useful as intermediate for the synthesis of fused pyrrolocarbazoles.